.problem-management {
  padding: 24px;
}

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.search-group {
  display: flex;
  gap: 12px;
}

.search-input {
  position: relative;
  width: 300px;
}

.search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 18px;
  height: 18px;
  color: #999;
}

.search-input input {
  width: 100%;
  padding: 8px 12px 8px 40px;
  border: 1px solid #e5e7eb;
  border-radius: 6px;
  font-size: 14px;
  outline: none;
  transition: all 0.2s;
}

.search-input input:focus {
  border-color: #1890ff;
  box-shadow: 0 0 0 2px rgba(24, 144, 255, 0.1);
}

button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 16px;
  border: none;
  border-radius: 6px;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-search {
  background-color: #f5f5f5;
  color: #666;
}

.btn-search:hover {
  background-color: #e8e8e8;
}

.btn-primary {
  background-color: #1890ff;
  color: white;
  gap: 8px;
}

.btn-primary:hover {
  background-color: #40a9ff;
}

.btn-icon {
  width: 16px;
  height: 16px;
}

.problem-table {
  background: white;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.03);
}

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 16px;
  text-align: left;
  border-bottom: 1px solid #f0f0f0;
}

th {
  background-color: #fafafa;
  font-weight: 600;
  color: #1a1a1a;
}

.difficulty-tag {
  display: inline-block;
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 500;
}

.difficulty-tag.easy {
  background-color: #e6f7e6;
  color: #52c41a;
}

.difficulty-tag.medium {
  background-color: #fff7e6;
  color: #fa8c16;
}

.difficulty-tag.hard {
  background-color: #fff1f0;
  color: #f5222d;
}

.action-buttons {
  display: flex;
  gap: 8px;
}

.btn-icon-only {
  padding: 6px;
  background: none;
  color: #666;
}

.btn-icon-only:hover {
  background-color: #f5f5f5;
  color: #1890ff;
}

.btn-icon-only.delete:hover {
  color: #f5222d;
}

.btn-icon-only svg {
  width: 16px;
  height: 16px;
}

.loading-row, .empty-row {
  text-align: center;
  color: #999;
}

.loading-spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 2px solid #f0f0f0;
  border-top-color: #1890ff;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-right: 8px;
}

.empty-state {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px;
  gap: 12px;
}

.empty-icon {
  width: 24px;
  height: 24px;
  color: #999;
}

.pagination {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 24px;
  padding: 16px;
  background: white;
  border-radius: 8px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.03);
}

.pagination-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

.btn-page {
  padding: 6px;
  background: none;
}

.btn-page:hover:not(:disabled) {
  background-color: #f5f5f5;
}

.btn-page svg {
  width: 16px;
  height: 16px;
}

.page-info {
  font-size: 14px;
  color: #666;
}

.page-size select {
  padding: 6px 24px 6px 12px;
  border: 1px solid #e5e7eb;
  border-radius: 6px;
  font-size: 14px;
  outline: none;
  cursor: pointer;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

@media (max-width: 768px) {
  .toolbar {
    flex-direction: column;
    gap: 16px;
  }

  .search-group {
    width: 100%;
  }

  .search-input {
    width: 100%;
  }

  .btn-primary {
    width: 100%;
  }
}
